Fixture stud for outlet boxes



Aug. 6, 1929.

H. G. KNODERER FIXTURE STUD FOR OUTLET BOXES Filed April 4, 1927 Inventor Homer G. Knoderer His Attorne Patente'd Aug. 6, 1929.

UNITED STATES PATENT OFFICE.

HOHER G. KNODERER, OF FAIRFIELD, CONNECTICUT, ASSIGNOR TO GENERAL ELEC- TRIC COMPANY, A CORPORATION OF NEW YORK.

FIXTURE STUD FOB OUTLET BOXES.

Application led April 4, 1927. Serial No. 180,725.

The present invention relates to electrical house wiring devices and more especially to junction or ceiling boxes and means whereby electroliers or other fixtures are supported.

The object of my invention is the provision of an improved fixture stud which may be easily installed upon an interjoist support and fixedl clamped on an outlet box in any adjuste position along the support. Junction and ceiling boxes are ordinarily installed before the walls and ceilings of a house are lathed and plastered and are for the purpose of providing outlets through the finished plaster for the electrical conductors installed within the partitions and bctween the floor joists. .After the plaster has become dry, the electric fixtures are installed thereon and the ends/of the installed conductors are respectively joined to the ends of the fixture conductors and a suitable finishing enclosure, such as a canopy, applied over the box and electrical connections. On account of the box and fixture being fixedly connected, it is necessary that the former be accurately positioned and securely supported in order to sustain the weight and stresses that a heavy electrolier or other fixture may thereon. e embodiment of my invention is shown in the accompanying drawing, in which Fig. 1 is a transverse section of a ceiling box, the sup orting-bar and the fixture stud in as sem led relation; Fig. 2 is a top plan vview thereof with the supporting bar shown broken; Fig. 3 shows at a reduced scale the method of attachment of the supporting bar to two floor joists; Fig. 4 is a transverse section of a modified form of xture stud and locking means; and Figs. 5 and 6 show '40 details for preventing .unscrewing of stud parts.

The ceiling box shown in the drawing is of standard and well known construction and is made of sheet steel with a central aper- 45 ture 1 in the bottom for the reception of the fixture stud, and between the central aperture and the side wall 2 are a plurality of apertures 3 each closed b a knockout plug 4 adapted to be readily isplaced to permit an electric conductor to be brought there-` through. The depth of the side walls 2 substantiall corresponds to the thickness of the com ined lath and plaster and the box is usually so positioned that the front edge of the side wall 2 is in the plane of the finished plaster.

The supporting bar 5 is a fiat rod of steel with holes punched in each end whereby it may be attached to the lower edges of floor joists 6 or other overhead structure by screws or nails, as indicated in Fig. 3.

The clamping fixture stud comprises two machined members 7 and 8 and a set screw 9. The upper member 7 is T-shaped with a transverse aperture 10 in the head 11 for the free reception of the supporting bar 5 and the shank 12 thereof is externally screw threaded and it has an axial aperture 13. The lower `member 8 of the stud has a screwthreaded shank: 14, a hexagonal head or flange 15 with a crown shoulder 16 adapted to freely enter the central box aperture l, an

internally threaded countersink 17 comple` mentary to the screw-threaded shank 12 of the upper member, and a small axial aper- ,ture 18 tapped for the reception of the set screw 9.

The upper member 7 of the fixture stud is threaded upon the supporting bar 5 prior to nailing or screwing the latter to the floor joists, the ceiling box is assembled thereon with thefshank 12 protruding through the central box aperture 1, the lower stud member 8 is screwed u on the threaded shank 12 of the upper mem r so that the wall of the box adjacent the hole 1 therein is firmly gripped between the lower edges of the T head of the up er member and the upper margin of the ange 15 of the lower member. YThe box with the fixture stud firmly .clamped thereto is free to be adjusted into any position lengthwise of the supporting bar 5, and when .in desired position it is secured by turning the set screw 9 so that its point firmly grips the bar 5 between itself and the opposite wall of the aperture 10 in the upper member.

The set screw 9, instead of being threaded in the lower member 8, ma be tapped into the upper member 7, asv indicated in Fig. 4. This arrangement also provides for holding the assembled parts of the stud during shipment.

In order to insure against any unscrewing tendenc of the lower stud member 9, the T head o the upper member ma have its lower surface provided with kni e edges 19 and a lock washer 20 interposed between the iange` and the innersurface of the box, as indicated in Fig. 5, so that when the members are screwed home any tendency to unscrew will be opposed by the gouging action of the knife edges and the lock washer ticular fixture. While l have shown and described the best form of the invention known to me, Ido not desire to be restricted thereto.

What l claim as new and desire to secure by Letters Patent ott the United States 1s:

1. A fixture stud for outlet boxes having a central aperture comprising upper and lower members, one of said stud members provided with a screw-threaded projection, the other member provided with a complementary screw-threaded recess and a screwthreaded projection, said members having vbearing surfaces for respectively engaging opposite surfaces of the box when the said members are assembled `on opposite sides vthereof and screwed home through the aperture therein.

2. A fixture stud -for outlet boxes commaaeee prising upper and lower members, said upper member provided with a transversely apertured head and a shank having an axial hole and an external screw thread, said lower member" having at its lower end a screw-threaded projection and at its upper end a vcomplementary threaded recess and a flange and an axial hole therethrough, and a set screw passing .through-said axial holes of bothimembers and having threaded engagement with one of vsaid members.

3. A xture stud for, assembly in outlet boxes having an aperture therefor, comprising an upper member provided with a head with a transverse aperture therethrough and on the lower sidethereof with box gripping means and a shank at its lower end, said shank being externally threaded and having an axial aperture extending therethrough and intersecting the transverse aperture of said head, a second or lower member havingv at its, upper end a polygonal flange and a recess complementarily threaded for the reception of the threaded shank of the upper member, said lower member having an axial aperture therethrough and an external thread on its lower end, and a'. set screw extending through said axial apertures into the transverse aperture of the upper member and having threaded engagement with one of said axial apertures.

In witness whereof, I have hereunto set my hand this first day of April, 1927.

HOMER G. KNODERER. 

